Portable electric lamp



Jan. 5, 1937. G. WHEAT PORTABLE ELECTRIC LAMP 2 Sheets-Sheet 1 Original Filed June I5, 1932 LLATTOR/v w N l/ENTOR.

Jan. 5, 1937. G. WHEAT PORTABLE ELECTRIC LAMP 2 Sheets-Sheet 2 Original Filed June 5, 1932 Patented Jan. 5, 1937 UNITED STATES PORTABLE ELECTRIC LAMP Grant Wheat, Marlboro Mass asslgnor to Kochler Manufacturing Company, Marlboro, Mass a corporation of Massachusetts Original application June 3, 1932, Serial No. '615,115. Patent No. 2,027,298 dated January Divided and this application February 24, 1934, Serial No. 712,739

2 Claims. (C1. 24010.6)

This invention relates to portable electric lamps of the general type shown in certain of my prior patents. While lamp structures of this general character were developed originally for use by miners, they have gone into rather general use in other. lines, either in approximately the forms illustrated in my patents, or in modifications embodying essentially the same ideas. They are ordinarily known as, 'n'iiners lamps.

In lamps of the commercial forms power is supplied by a storage battery which usually is slung from the wearer's belt, or is carried on some' other part of the person. Such batteries must be charged at suitable intervals. In most mines it is the custom for miners to leave their lamps in the lamp house where they are placed on charge immediately after the miners have left the mine, and they take their lamps again before going into the mine. Because of the fact 20 that these lamps are designed primarily for use in mines where they must be expected to operate in explosive atmospheres, it is extremely important to prevent any possibility of a spark occurring either due to some incident in the nor- 5 mal operation of the apparatus, or due to the mischievous tampering or experimenting with the lamp structure by the miners themselves.- This introduces a problem in the charging of the batteries because of the desirability of having the 30 terminals located in some exposed or readily accessible position so that the batteries can quickly be placed on charge when they. are left at the lamp house. To devise a thoroughly practical solution for this problem forms the chief object 35 of the present invention.

The nature of the invention will be readily understood from the following description when read in connection with the accompanying drawings, and the novel features will be particularly pointed out in the appended claims.

In the drawings,

Figure 1 is a perspective view of a lamp structure embodying features of this invention;

. Fig. 2.is a diagram of the circuit connections 45 of the apparatus shown in Fig. 1;

Fig; 3 is a plan view, withparts' broken away, of the thermostatic switch in the headpiece shown in Fig. 5; i

Fig. 4 is a sectional view ,of said thermostatic 50 switch;

Fig. 5 is a perspective view of the headpiece shown in Fig. 1, but with the bezel, lens, refiector and main lamp removed;

Fig. 6 is a view, partly in vertical section and partly in side elevation, of the headpiece shown 5 in Fig. 1;

Fig. 7 is a vertical, sectional view of a battery casing top including certain of the control elements which are mounted in the headpiece of the construction shown in Fig. 1; 10

Fig. 8 is a perspective view of the rotating elementof the switch shown in Fig. 13; and

Fig. 9 is a perspective view of a magnetic switch which may be substituted for the thermostatic switch shown in certain of the other figures. 15

Referring first to Fig. 1, the lamp structure there shown comprises a headpiece or lamp casing 2 equipped with a spring actuated clamping device 3 for gripping the edges of a metal plate 4 which is secured to the front of a miners cap 5 so as to hold the headpiecesecurely on the cap. A cable 6, including suitable electric conductors, operatively connects this headpiece with a storage battery I slung from the wearer's belt a.

Referring more especially toFigs. 5 and 6, it will be observed that the main lamp III is mount-. ed in the headpiece immediately in front of a concave reflector l3. Preferably it consists of an'incandescent electric lamp of a special type having two filaments l6 and I1 and provided with two end terminals l8 and I 9, respectively, these terminals being connected to the respective leading-in wires 20 and 2 I. The middle lead wire 22 is electrically connected to the metal base It. The connections for conducting current to this lamp comprise two leaf springs 24 and 25, secured in the headpiece, with their ends positioned to bear, respectively, on the two terminals l 8 and [9. The lamp base is straddled by a forked spring 28 having depressions in its arms to receive the pins l5 at opposite sides of the base. These springs 24, 25 and 26'. exert a downward pressure on thelamp bulb, and it is supported against this pressure by a spring arm 21 secured firmly to the casing and curved and forked at its forward end to partly embrace the lower end of the bulb ill, the construction being such that it tips this bulb backwardly against the reflector.

Th s construction is. of value in breaking the, en-

gasement of the terminals l8 and I 9 with the contacts 24 and 25, in the event that the lamp bulb becomes broken.

The lamp structure also includes an emergency lamp bulb l2 located chiefly behind the reflector I I and supported in a suitable socket.

In order to enable the operator to use either filament IE or I! of the main lamp, or to turn on the emergency lamp I 2, as he may desire, an electric switch is mounted in the headpiece and comprises a switch arm 33, Figs. 2 and 5, connected directly with the button 35, Fig. 1, mounted on the outside of the headpiece 2, the switch arm being arranged to engage the ends of either of the contacts 24 or 25, or with another contact 34 which is connected with the spring contact of the emergency lamp socket. One terminal of the battery is connected to the switch arm 33, while the other is connected to those members which receive or engage the bases of the lamps l0 and I2.

For convenience in charging the battery, two charging terminals 5|5l, Figs. 1 and 6, are located at opposite sides of the neck or shank of the headpiece and in exposed positions, as shown in one of my earlier patents, and in order to prevent the miner from short-circuiting the battery simply by connecting these terminals with a wire, or some other conductor, they are connected to the battery through a switch which not only is normally held open, but is entirely out of the miner's control. In addition, it is desirable to reduce the duties oi the attendant at the lamp house and, in fact, to avoid the necessity for an attendant in the lamp house of a small mine. Consequently, the present invention proposes not only to take the charging circuit out of the control 01' the miner, but also to provide such an arrangement that the miner can charge his own battery simply by placing it in'the proper position in the charging rack when he leaves the mine, and turning the switch to a given position.

Referring more particularly to Fig. 5, it will be seen that the switch arm 32, previously mentioned, is arranged to engage an additional contact 52 which is connected with one of the chanting terminals 5|. The switch I! is continuously connected with one terminal 0! the battery while the other battery terminal is connected through a thermostatic switch 53 to the other charging terminal 5|. This switch is best shown in Figs. 3 and 4. It includes a bi-metallic strip 54 around which is wound a coil 55 of resistance wire. The strip carries a contact 56 adapted to engage a stationary contact 51 which is carried by, but is insulated from, the switch base. A casing encloses the switch parts. Normally the bi-metallic strip 54 is warped or sprung to such an extent that it holds the contact 56 out of engagement with the contact 51 and, consequently, maintains the charging circuit open. As soon, however, as the lamp is properly placed in the charging rack a current flows from one charging terminal 5| through the resistance coil 55 and the thermostatic switch 5| back to the other charging terminal. This raises the temperature of the thermostatic switch and causes its free end toswing toward the stationary contact 51, thus closing the switch. It the manually operated switch a: has previously, or is now, moved to bring its arm 23 into engagement with the contact 52, a charging current then will flow through thebattery I. When the miner takes his lamp out of the charging rack in the morning, it is simply necessary for him to turn the switch arm 33 far enough to light one 01' the filaments IE or IT, and he can then go to work. The bi-metallic strip 54 cools of! rapidly and opens the thermostatic switch very shortly after the lamp has been removed from the charging rack.

- This construction, therefore, enables the miner to recharge his own lamp, and in many mines makes it unnecessary to keep a man on duty at the lamp house.

Instead of using a thermostatic switch an electro-magnetic switch may be substituted for it. Such a construction is shown in Fig. 9. It includes a core 60 with an energizing winding Oi which is connected across the charging terminals in the same way that the resistance wire 55 is connected in the diagram shown in Fig. 2. Located within the field of this magnet is an armature G2 carrying a contact 63 arranged to engage cooperating stationary contacts 64. This switch 63 -64 is connected in the charging circuit in the same way as the switch 58-51 in Fig. 2. Its operation is essentially the same. It is. however, slightly larger and heavier than the thermostatic switch, and the latter is preferred for this reason.

Instead of having the control units above described all mounted in the headpiece, it is possible to transfer some, or all of'them, to the battery casing. Such an arrangement is illustrated in Figs. 7 and 8 in which the thermostatic switch II is connected to the charging terminals 85-" in essentially the manner above described, these terminals, howevenbeingnnuntedinthetopoi the battery casing. Also located in the casing top is a switch consisting ot a rotary shaft 00 having a metal switch segment 81 arranged to electrically connect a central terminal as with either of two side terminals II or II. In the position of the parts shown in Fig. '1. the two contacts I and II are electrically connected, and the battery is ready for the charging operation. when, however, the switch knob 08 is turned to electrically connect the contacts 02 and II, the charging cir cult then is broken, and the headpiece is electrically connected with the battery. Even when this arrangement is used, however, it is preferable to mount a switch on the headpiece for turning the current on to either of the filaments o! the main lamp II or on to the emergency lamp l2, as circumstances may require.

The invention thus provides a portable lamp structure in which the charging of the battery is facilitated, while at the same time minimising the danger of creating a spark or injuring the appsratus itself, either accidentally or through tampering by the miners.

While I have herein shown and described preferred embodiments 01' my invention, it will be understood that the invention may be embodied in other forms without departing from the spirit or scope thereof.

The present application is a division of my copending application Serial No. 615,115, filed June 3, 1932, which has matured into Patent #2027298, Jan. 7, 1936, the claims in the present case being limited to the construction provided to facilitate charging, while thou in the parent case are directed to other features 01 the invention disclosed in the latter application.

Having thus described my invention, what-I desire to claim as new is:

1. In a miner's lamp, the combination with a headpiece adapted to be secured to the miner's clothing, said headpiece including a casing, an electric lamp bulb mounted in said headpiece, a

storage battery, a casing for said battery and circuit connections for operatively connecting said battery with said lamp bulb, of exposed charging terminals on one of said casings adapted to be connected with an outside source of current .to charge said battery, a charging circuit for connecting said terminals with'said battery, said charging circuit including a. normally open switch located in one of said casings for maintaining said battery electrically disconnected from one of said'terminals whereby the latter terminal is normally maintained electrically dead, a control circuit permanently connecting said charging terminals, and means in said control circuit arranged to be ,operated by the flow of current therethrough for operating said normally open switch to close it.

2. In a miners lamp, the combination with a headpiece adapted to be secured to the miners clothing, an electric lamp bulb mounted in said headpiece, a storage battery, and circuit connections for operatively connecting said battery with said lamp bulb, of exposed charging terminals on said headpiece adapted to be connected with an outside source of current to charge said battery, a charging circuit for connecting said terminals with said battery, said charging circuit including. a normally open thermostatic switch in the lamp for maintaining said battery normally disconnected electrically from one of said terminals, whereby the latter terminal is normally maintained in an electrically dead condition, and a control circuit forsaid switch permanently connecting said charging terminals and including a coil for heating the thermostatic element of said switch.

GRANT WHEAT. 

